1. Field of the Invention
The present invention relates to a solid-state imaging device that converts received light into electrical signals and outputs them as video signals.
2. Description of Related Art
Solid-state imaging devices that convert received light into electric signals and output them as video signals have been known before now. Digital cameras that display images on the basis of video signals obtained from these solid-state imaging devices also have been known. Recent years have seen the need for better image quality and functionality in cameras featuring such solid-state imaging devices, and there has been growing demand for higher pixel density.
In an effort to raise the speed at which video signals are outputted in such solid-state imaging devices in order to achieve a moving picture display, for example, a drive method has been proposed in the past in which the number of pixels included in an output video signal is reduced by thinning out the pixels from which signal charges are read.
For example, JP 2004-180284A and 2005-166826A disclose a construction in which last transfer stages (split transfer components), which are the transfer stages of vertical transfer components that are closest to a horizontal transfer component, have identical transfer electrode configurations repeated every m (m is an integer of 2 or greater) columns, and vertical final stages of columns other than one of the m columns, or the vertical final stages of all the columns, are each provided with an independent transfer electrode that is independent of other columns so that an operation of transferring from the vertical final stages to the horizontal transfer component is controlled independently of the other columns. With this construction, the transfer from the vertical transfer components to the horizontal transfer component is combined with the transfer in the horizontal direction by the horizontal transfer component, which allows the pixel output to be rearranged or mixed as desired, and affords faster output of video signals.
FIG. 33 is a cross-sectional view of the structure of the split transfer component disclosed in the above-mentioned JP 2005-166826A. This split transfer component has a drive electrode with a two-layer structure comprising a first layer of polysilicon (not shown) laminated with a second layer of polysilicon 260, a first wiring 270, which is an aluminum layer that also serves to block light from the vertical transfer components (not shown), a second wiring 280 that is formed from tungsten and also serves as a light blocking film, and a contact plug 290 that electrically connects the first wiring 270 and the second polysilicon layer 260.
However, with the construction shown in FIG. 33, in the region directly under the OB region (the region between the horizontal transfer component and the OB region provided to the left and right of the effective pixel region), light leaks in from the gaps between the plug 290 and the second wiring 280, which is a problem in that it causes improper OB clamping.